291
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 392
- Proper Divisor Sum (Aliquot Sum)
- 101
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 192
- Möbius Function
- 1
- Radical
- 291
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 117
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- zweihunderteinundneunzig· ordinal: zweihunderteinundneunzigste
- English
- two hundred ninety-one· ordinal: two hundred ninety-first
- Spanish
- doscientos noventa y uno· ordinal: 291º
- French
- deux cent quatre-vingt-onze· ordinal: deux cent quatre-vingt-onzième
- Italian
- duecentonovantuno· ordinal: 291º
- Latin
- ducenti nonaginta unus· ordinal: 291.
- Portuguese
- duzentos e noventa e um· ordinal: 291º
Appears in sequences
- a(n) = floor(n^(3/2)).at n=44A000093
- Construct a triangle as in A036262. Sequence is one less than the position of the first number larger than 2 in the n-th row (n-th difference).at n=19A000232
- Dimension of the n-th graded piece of the mod-2 Steenrod algebra A_2.at n=64A000929
- Number of functional digraphs (digraphs of functions on n nodes where every node has outdegree 1 and loops of length 1 are forbidden).at n=8A001373
- Number of partitions of n into at most 5 parts.at n=23A001401
- a(n) = 3 * prime(n).at n=24A001748
- Numbers k such that 13*2^k - 1 is prime.at n=4A001773
- Number of forests of trees on n labeled nodes.at n=5A001858
- v-pile positions of the 4-Wythoff game with i=3.at n=55A001968
- Numbers k for which the rank of the elliptic curve y^2 = x^3 - k is 2.at n=37A002154
- a(n) = floor(3^n / 2^n).at n=14A002379
- Number of integral points in a certain sequence of closed quadrilaterals.at n=24A002579
- a(n) (n>6) is least integer > a(n-1) with precisely three representations a(n) = a(i) + a(j), 1 <= i < j < n, a(n) = n for n=1..6.at n=57A003045
- Problimes (second definition).at n=52A003067
- Positions of letter c in the tribonacci word abacabaabacababac... generated by a->ab, b->ac, c->a (cf. A092782).at n=46A003146
- Numbers that are the sum of 6 positive 4th powers.at n=21A003340
- Numbers that are the sum of 11 positive 4th powers.at n=34A003345
- Numbers that are the sum of 12 positive 5th powers.at n=11A003357
- Divisors of 2^48 - 1.at n=28A003553
- Numbers whose binary expansion ends in 011.at n=35A004769